LECTURE XXV. 

 POISONOUS PLANTS. 



WOOLLY LOCO WEED, {Astragalus moWsslmus). 



This plant belongs to the pea family and is quite well known, 

 (especially in the northwestern plains country. "Silvery white, 

 ^ilky leaved perennial, eight to twelve inches high, with an abund- 

 ance of soft foliage springing out in a cluster from a short cen- 

 tral stem close to the ground. The flowers are pea shaped and 

 •usually purple." (Chestnut.) 



Susceptible animals. — Horses are most seriously injured. 

 'Cattle and sheep may be affected to some extent, but the finan- 

 • cial loss with them is not serious. 



STEMLESS LOCO WEED, [Aragallus kmbertu). 



This plant is quite different from the preceding, growing 

 very erect and with few branches. The leaflets are longer and 

 the seed pod has but one cell instead of two. It grows over 

 about the same territory as the woolly loco. The symptoms of 

 ; poisoning are apparently identical with those of the woolly loco. 

 This plant has about the same range as the preceding — being 

 ■found especially in the northwestern and western range countries. 



Symptoms. — The effect of this poisoning is quite slow in 

 its appearance, and there develops in the affected animal some- 

 ■thing of a habit or desire for the weed. 



During the first stage of loco poisoning the horse seems to 

 be a little out of balance mentally, and the eye sight is impaired. 

 After awhile the horse becomes so fond of this plant, that he 

 seems to prefer it to grasses or other food which he might easily 

 obtain. 



The second stage is a long period of general atrophy, the 

 animal being tliin and weak. The hair is dull, and the expres- 

 sion is one of feebleness. The total period of illness may last 

 -.from a few months to two years. 



